CA 02532984 2006-O1-18
BACKGROUND
[0001] In facilities, e.g. buildings or installations, where a significant
amount of
power is used among a variety of units, it would be desirable to allow the
building owner
to allocate energy costs to the different units, i.e. consumers, within the
facility. For a
commercial office building, these units may include the different tenants
within the
building or the common loads for the facility, such as the elevators or HVAC
systems.
For an industrial facility, these units may include the different production
lines, machines
or processes within the facility. As opposed to allocating costs based on a
fixed or
formulaic approach (such as pro-rata, e.g. dollars per square foot or based on
the
theoretical consumption of a process/machine), an allocation based on actual
measurements using appropriate monitoring devices may result in more accurate
and
useful information as well as a more equitable cost distribution.
[0002] Both installation and ongoing, i.e. operational and maintenance, costs
for these
monitoring devices are important considerations in deciding whether a
monitoring system
is worth the investment. While monitoring devices may be read manually, which
does
not increase the installation cost, manual data collection may increase on-
going/operational costs. Alternatively, monitoring devices may be
interconnected and be
automatically read via a communications link. However, typical communication
links
require wiring to interconnect the devices which increases the installation
cost. In
addition, a particular tenant in the building may wish to verify that they are
being billed
correctly by reading the energy meter or other energy monitoring device that
is
accumulating their energy usage. This may be a straightforward, although labor
intensive
and cumbersome, process with a typical energy meter which provides a display
viewable
by the tenant.
[0003] Emerging wireless mesh (or ad-hoc) networking technologies can be used
to
reduce the installation costs of monitoring devices while providing for
automated data
collection. Also called mesh topology or a mesh network, mesh is a network
topology in
which devices are connected with many redundant interconnections between
network
nodes. Effectively, each network node acts as a repeater/router with respect
to received
communications where the device is not the intended recipient in order to
facilitate
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communications between devices across the network. Using wireless
interconnections
permits simpler and cost-effective implementation of mesh topologies wherein
each
device is a node and wirelessly interconnects with at least some of the other
devices
within its proximity using RF based links. Mesh networking technologies
generally fall
into two categories: high-speed, high bandwidth; and low speed, low bandwidth,
low
power. The first category of devices are typically more complex and costly
that the
second. Since energy monitoring does not typically require high speed/high
bandwidth
communication, the second category of devices is often sufficient in terms of
data
throughput.
[0004] Energy monitoring devices may include electrical energy meters that
measure
at least one of kWh, kVAh, kVARh, kW demand, kVA demand, kVAR demand, voltage,
current, etc. Energy monitoring devices may also include devices that measure
the
consumption of water, air, gas and/or steam.
SUMMARY
[0005] The present invention is defined by the following claims, and nothing
in this
section should be taken as a limitation on those claims. By way of
introduction, the
preferred embodiments described below relate to a monitoring device for
monitoring
electrical energy consumed by an electrical load. The monitoring device
includes: a
current sensor operative to sense actual current flow in at least one power
line which is
supplying electrical energy to the load, the at least one power line being
further
characterized by an actual voltage value associated with the actual current
flow, the
current sensor being further operative to generate an analog signal indicative
of the
amount of actual current flow sensed in the at least one power line; an analog
to digital
converter coupled with the current sensor and operative to convert the analog
signal to a
digital representation of the amount of the actual current flow; an assumed
voltage value
of the at least one power line, wherein the assumed voltage value may be
different than
the actual voltage value, the assumed voltage comprising an approximation of
the actual
voltage value; and a processor coupled with the analog to digital converter
and the
assumed voltage value and operative to calculate at least one measure of power
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consumption by the electrical load based on the digital representation, the
calculation
being further based on the assumed voltage value instead of the actual voltage
value.
[0006] The preferred embodiments further relate to a method of monitoring
electrical
energy consumed by an electrical load. In one embodiment, the method includes:
sensing
actual current flow in at least one power line which is supplying electrical
energy to the
load, the at least one power line being further characterized by an actual
voltage value
associated with the actual current flow; generating an analog signal
indicative of the
amount of actual current flow sensed in the at least one power line;
converting the analog
signal to a digital representation of the amount of the actual current flow;
providing an
assumed voltage value of the at least one power line, wherein the assumed
voltage value
may be different than the actual voltage value, the assumed voltage comprising
an
approximation of the actual voltage value; and calculating at least one
measure of power
consumption by the electrical load based on the digital representation, the
calculating
being further based on the assumed voltage value instead of the actual voltage
value.
[0007] Further aspects and advantages of the invention are discussed below in
conjunction with the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 depicts a block diagram of a commercial building incorporating
the
system of the present invention.
[0009] Fig. 2 depicts a block diagram of the internal circuitry of an example
of an
energy monitoring device of the present invention.
[0010] Fig. 3 depicts a block diagram of a first procedure retrieving a
verified energy
reading from the energy monitoring device of the present invention.
[0011] Fig. 4 depicts a block diagram of a second procedure retrieving a
verified
energy reading from the energy monitoring device of the present invention.
[0012] Figs. 5-6 depict an exemplary method of mounting a monitoring device
according to one embodiment.
[0013] Figs. 7-8 depict exemplary commissioning reports according to one
embodiment.
[0014] Figs. 9A-9C depict an exemplary CT locking device.
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[OOIS] Figure 10 depicts exemplary voltage waveforms and time relationships
for
several possible current waveforms according to one embodiment.
[0016] Figure 11 depicts an exemplary voltage displacement device for use with
the
disclosed embodiments.
[0017] Figure 12 depicts a block diagram of an alternate commercial building
incorporating the system of the present invention.
[0018] Figure 13 depicts an exemplary process for using assumed data values in
computations according to one embodiment.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0019] Herein, the phrase "coupled with" is defined to mean directly connected
to or
indirectly connected through one or more intermediate components. Such
intermediate
components may include both hardware and software based components. Further,
to
clarify the use in the pending claims and to hereby provide notice to the
public, the
phrases "at least one of <A>, <B>, ... and <N>" or "at least one of <A>, <B>,
... <N>, or
combinations thereof' are defined by the Applicant in the broadest sense,
superceding
any other implied definitions herebefore or hereinafter unless expressly
asserted by the
Applicant to the contrary, to mean one or more elements selected from the
group
comprising A, B, ... and N, that is to say, any combination of one or more of
the elements
A, B, ... or N including any one element alone or in combination with one or
more of the
other elements which may also include, in combination, additional elements not
listed.
[0020] In general herein, a public key is a number, formula, algorithm,
function, etc.
that is made, or intended to be, publicly available, i.e. made available to
any user that
wants it. A private key is a number, formula, algorithm, function, etc. that
is intended to
be kept private and is protected in some way from access. This protection may
be in the
form of secrecy, an enclosure, encryption, difficulty in access, etc. The more
difficult it is
to circumvent the protection, the better, however it will be appreciated that
the utility of
the disclosed examples is not dependent on the quality of the protection the
private key.
[0021] An energy monitoring device that is designed to transmit its
measurement
values may not be accessible to be manually read by a person. This may be due
to the
fact that the energy monitoring device does not have a display or is otherwise
physically
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inaccessible, and although the device may provide a communications pathway
(wired or
wireline) allowing it to be accessed by the energy provider, the device may
not provide a
direct communications pathway for the user. This causes a problem in that the
user/consumer of the energy being monitored by the energy monitoring device
may be
left with no way of verifying that they are being billed accurately for the
usage that their
respective energy monitoring device is measuring. For instance, a
configuration error
may result in the user being billed based on an incorrect or mis-configured
energy
monitoring device or the user may simply not trust the energy provider to
provide an
accurate accounting of energy consumed.
[0022] The following description details various mechanisms for verifying the
integrity of readings taken from electrical monitoring devices which axe in
communication with a central computer through a mesh network. It will be clear
to those
skilled in the art that the mechanisms defined herein are also applicable to
monitoring
other parameters indicative of energy consumption.
[0023] Public/private keys may be used for authenticating a message sent from
one
computer to another computer over communications pathways such as the
Internet. In
general, a message can be authenticated by performing a function (such as a
hash) on the
message data with a private key of one computer. A second computer can then
verify the
origin of the message by performing a corresponding function on the results of
the first
function and the message data using the first computer's public key.
[0024] Figure 1 depicts an exemplary commercial office building 100 for use
with the
disclosed embodiments. The commercial office building 100 has a number of
floors 110.
Each floor may contain an electrical room 130. Alternatively there may be more
than one
electrical room 130 per floor or only one electrical room 130 per a number of
floors.
Within each electrical room 130 there may be one or more energy monitoring
devices 120
within an energy monitoring system 101. It will be appreciated that the
location of the
energy monitoring devices 120 is implementation dependent and that they need
not be
located in an electrical room 130. The energy monitoring devices 120
communicate
among each other to form a mesh network, depicted in Figure 1 by multiple
communications links 140 shown between the energy monitoring devices 120. It
will be
appreciated that fewer or more communications links 140 may be used between
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monitoring devices 120 and that the availability of a communications link 140
between
any two monitoring devices 120 may fluctuate depending upon conditions such as
interference, etc. Repeaters 155 may also be provided to facilitate
communications
between two devices 120 which may not otherwise be able to communicate due to
distance, interference, etc. Alternatively, one device 120 may have two
antennas which
operate at different power levels, gains, frequencies, modulation schemes,
etc. to
overcome interference, distance, etc. One of the antennas may be connected to
a long
cable (such as a coaxial cable) in order that the antenna may be located
remotely from the
device 120 in a more effective location for transmission/reception than the
device 120.
Alternatively, the architecture may provide a wireline segment 156 where
communications between two devices are not possible otherwise. This may happen
due
to distance, interference, shielding, etc. The mesh network may use the
wireline segment
156 in a similar fashion to the communication links 140. The wireline segment
I 56 may
be implemented using power line Garner techniques over the office building 100
power
lines or using standard wireline communications/networking architectures such
as RS-
485, RS-232, Ethernet, etc.
[0025] The device 120 may facilitate the replacement of its antennas such that
for a
given installation location, flexible, such as rubber encased or flexible
wire, adjustable,
directional, high gain, or different propagation pattern antennas may be
substituted to
facilitate more reliable communications. Further, antenna enhancing devices or
devices
which enhance RF transmission by utilizing proximate structural elements such
as metal
casings, glass windows, etc., may also be used
[0026] The mesh network also encompasses a gateway I50 which facilitates
communications with a computer 160 or other computing device. The computer 160
may
communicate energy data and other data over a LAN 170. The computer 160 and
gateway 150 communicate over a serial or other form of communication link.
Alternatively, the gateway I50 may interface with the LAN 170 directly and the
computer
160 may be connected to the LAN 170 in a different part of the building 100
and
communicate with the gateway I 50 over the LAN 170. The computer 160 may
receive a
time reference from a GPS satellite 185. Alternatively, the GPS satellite 185
signal may
be received by an energy monitoring device 120, gateway 150 or repeater 155
within the
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mesh network. In this alternate case, the time within the alternate device
becomes the
reference for the energy monitoring system 101. The LAN 170 may interface to a
WAN
171 such as the Internet. The gateway 150 may, for example, be located in a
chief
engineer's office where a connection to the LAN 170 is readily available.
There may be
more than one gateway 150 in the energy monitoring system 101 facilitating
extraction of
data from the system at more than one point in the mesh network. The gateways
150 may
communicate over the LAN 170 to a concentrator that aggregates information
from all the
gateways.
[0027] With present mesh networks it is often difficult to determine the
health/status
of the network. Typically, only basic information is available from any given
node, such
as the ability of the node to communicate with the gateway and the signal
strength for
closest node, both of which give no indication of redundant paths or
communication error
rates, or other more detailed status information. Often after a network is
installed,
unhealthy networks, e.g. network with one or faulty links or devices, are
identified
through missing data or low percentage of responses to requests. The need
exists to have
an easy low cost way to determine health/status of the network especially
during
installation of a system.
[0028] In one embodiment, a data aggregation device, which may be a portable
communications device 180, or other device coupled with the mesh network such
as the
gateway 150 or computer 160, or software executing thereon, provides the
ability to
gather network status/statistical information from the mesh network via
self/automated
reporting by the devices which make up the network. Such self reported data
may
include perceived signal strength, delivery delays, multiple or confusing
responses, non-
responsive or slow responding nodes, communications errors, etc. Further, this
data may
include both current and historical data collected over a period of time. Such
reporting
facilitates the identification of weak network links, failing nodes, redundant
paths, etc.
The reporting may also take place via the display or local communications
connection of
the particular device to allow a physically proximate user to assess and view
the network
status as perceived by that particular device. In an alternate embodiment,
each device
may report the status information of other devices as well, such as other
nodes/devices
which are proximate to the particular device. At the point of data
aggregation, this
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reported data may be collected/aggregated and reported to a user to present an
overall
network status of the entire network, or a particular portion thereof, such as
by a graphical
presentation or the like which shows failing links, links with high error
rates, low signal
strength, etc. possibly using colors or other visual indicators.
(0029] In an alternate embodiment, rather than rely on a self reporting
mechanism, or
in addition thereto, diagnostic packets may be sent or requested from each
node over the
wireless link containing data used by the gateway to identify weak or failing
links or
nodes in the radio network. The diagnostic packets may contain such
information as
signal strength of all neighboring nodes in priority of use and number of
redundant paths.
This data would then be used by the gateway to determine if additional
repeaters are
needed in specific locations. In one embodiment, diagnostic packets are
capable of being
directed over particular network paths of the mesh network to focus diagnostic
activity on
particular areas of the network.
[0030] Where weak links or troublesome nodes are discovered, measures could be
taken to increase communication reliability. For nodes that have weak links to
the rest of
mesh network, for example communications may be attempted more often in an
effort to
effectively increase the chances that some of the communications will get
through during
periods of reliable connectivity and causing the mesh network to seek better
links with
this device.
[0031] Many issues with mesh networks occur upon installation of the network
and
may be resolved at that time, prior to actual use and reliance on the network.
For
example, during the installation of a large number of meters, such as can be
found on a
commercial building meter installation (typically 100 meters or more), a
fairly high
probability exists that one or more of the devices will be installed
incorrectly.
Furthermore, some devices may have limited error detection capability due to
limitations
in their memory capacity/code space and are only be able to detect simple and
obvious
errors. Typical errors which simpler devices typically detect include: wrong
phase
connections, reversed CT connection or bad CT and phase connections
(open/shorted).
[0032] In one embodiment, the capability to generate an automated
commissioning
report from the different devices is provided. The commissioning report is
generated by
first obtaining assorted real time device data from all of the operating
devices and then
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analyzing the real time values for validity. The real time device data may
include RMS
current and voltage readings, frequency, apparent (VA) power, real(W) power
and
reactive (VAR) power and power factor. Using a combination of these values, in
conjunction with the measuring mode (delta or wye), angles can be determined
between
voltage and current phases. For example, if the real power is negative and in
the
installation it is known to be positive, i.e. since power is being delivered,
this may
indicate that the current transformer ("CT") could be reversed. For devices
that can
automatically compensate for a reversed CT, a warning would be provided
indicating that
the CT phase is reversed.
[0033] In this embodiment, every device in the installation is automatically
interrogated when the device is initially detected in order to provide an
entry for the
commissioning report. Expert system software is provided at the point of data
aggregation which uses common sense relationships to analyze the data and
determine if
the readings are reasonable. The installer will go over the commissioning
report and
evaluate each error or warning for validity. For example, if voltage and
current from I2
are reported to be zero on a floor/panel, and the installer knows there are no
loads on the
circuit, then the reading is reasonable. However if there is expected to be a
reading, then
there is something wrong with the CT, connections or configuration and the
installer can
take corrective action. An exemplary table based commissioning report is shown
in
Figure 7.
[0034] The commissioning report may be further enhanced by providing relative
phase angles between all the current and voltage phases. This information may
be
provided by a device such as the ION 6100 power meter, manufactured by Power
Measurement, Ltd., located in Saanichton, British Columbia, Canada. Using the
phase
angles, swapped current or voltage phases may be easily determined. To
simplify the
presentation, the commissioning report may simply provide a vector diagram (as
found on
ION 7500 power meter, also manufactured by Power Measurement, Ltd.) for each
device
with an appropriate OK, WARNING or ERROR message. This would reduce the
clutter
of a large number of real time reading values. Figure 8 shows an exemplary
vector based
commissioning report.
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[0035] The installation of mesh networks using monitoring devices, such as the
ION
6100 mesh network based power meter, can be complicated by intermittent
network
connections due to marginal transmission and reception of data over the
network.
Typically, during the commissioning of the system, all that can normally be
done is to
verify that each device in the network communicates with a central gateway.
This
verification simply tells the installer that the system is currently working
properly, but it
does not tell how much operating margin the radios have. For low cost devices,
it is
usually not feasible to include measurement of signal strength.
[0036] The operating conditions of a mesh network radio can change due to near
body
effects, temperature, interference, fading and mufti-path, etc. If node
reception, i.e. signal
strength or connection quality, is close to the operating limit of the radio,
then small
changes of the operating conditions may render a node non-communicating.
(0037] In one embodiment, the use of a variable power mesh network node is
provided to validate the correct operation of the system at a reduced power
level. During
commissioning, the system is switched to a lower power mode which operates the
radios
at a lower power level than the radios are normally capable of. Once the
system has been
verified to be fully operational (which may require the installation of
appropriate routers
to complete the network), the system is switched to the normal operating mode
at the
normal radio power. During normal operation, the mesh network node power will
be
increased to a higher (normal) power level assuring that the reception and
transmission of
mesh network data is well above any marginal radio operating parameter.
[0038] In yet another embodiment, the monitoring devices feature the
capability to be
located a inside or proximate to a circuit breaker with the monitoring
device's current
transducers being coupled with the breaker's loads and sending data to the
monitoring
device/meter. The current transducers also feature mesh network capability,
i.e. RF
communications capabilities as described herein, and communications between
the
device/meter and the current transducers is accomplished via a mesh
communications
network or other medium. In this embodiment, the device/meter is physically
configured
to fit within a particular form-factor of the breaker panel.
[0039] In yet another embodiment, the mesh network may include nodes mounted
to
elevators, or other moving mechanical systems, and utilizing the movement of
the
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elevator to bring the elevator-mounted node within a communications-proximity
to
portions of the mesh network which are otherwise inaccessible. The elevator
mounted
node may act as a store and forward device facilitating communications between
other
network devices as connections are established and lost due to its movement.
The
elevator mounted node may store data from particular devices until the
elevator moves to
another location where forwarding of the data is possible or alternatively,
the elevator
mounted node may use alternate communications means such as higher power 1RF
or
wireline communications to forward the data.
(0040] In yet another embodiment, the mesh network of monitoring devices
further
include a capability to share common area usage charges based on actual or
more closely
approximated usage of common areas. The monitoring devices or central
aggregation
device may feature the capability to discern usage of common areas by
particular tenants,
or at least make approximations of such usage. Where reasonable approximations
of
particular tenant usage may be determined and associated with particular
consumption,
that consumption may be appropriately charged to the particular tenant. For
example,
power consumption by the elevators may be apportioned to tenants by the floors
which
they occupy such that a tenant which occupies multiple floors or is a frequent
elevator
user is apportioned a more appropriate amount of the charges associated with
operating
the elevators. Other methods of approximating particular tenant usage of
common areas
may rely on building access identifications cards and their use at particular
access points
throughout the facility or 1tF enabled identification badges which permit
tracking of
tenant movement throughout the facility. Further, temperature sensors, or
other coupling
with environmental control systems, may be provided to measure HVAC usage in
particular areas to properly apportion those costs.
[0041] A user 190 may transport a portable communication device 180 axound the
building 100. This portable communication device 180 may be used to read
energy
registers from the various energy monitoring devices. The portable
communication
device 180 and the energy monitoring device 120 may both have indicators (such
as
LEDs) on them that light, or otherwise signal, when communication is
established
between the two devices. This indicates to the user that they are in
communication with
the correct energy monitoring device 120. In addition, the portable
communication
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device 180 may read a secondary register from the energy monitoring device 120
which is
a hash of the energy registers and a pattern such as the private key of the
energy
monitoring device 120. If the pattern is known only to the energy monitoring
device and
a system such as a billing system within a utility, the registers within the
portable
communication device will be difficult to tamper with without detection. The
secondary
register may appear to the user of the portable communication device 180 as
just another
register such that the user is not aware that the secondary register may be
used for tamper
detection. The portable communication device 180 may be a handheld meter
reader.
[0042] In one embodiment, a handheld device is provided for performing
network/device related tasks, such as optimizing monitoring device (or
antenna) locations
for optimal communication performance, performing routine monitoring of
network
status, determining or monitoring for specific device availability or
activity, determining
device locations (by proximity or by using GPS capabilities), communicating
with
devices via the mesh network and/or direct/local device interfaces, such as
for setting
up/initializing devices, and acting as a mesh enabled data display.
[0043] When installing wireless meters/nodes it may be advantageous for the
electrician or commissioning engineer to have a separate handheld radio that
is used to
determine suitable positioning of the devices being installed. The handheld
radio would
be able to communicate with the network being installed and have a faster rate
of
communication with the gateway 150. 'The rate of communication with the
gateway 150
could be configurable to suit all sizes of networks. The handheld radio may
have a
display or some other user interface such as LED's to help determine radio
link quality
into the network.
[0044] Alternatively each device being installed could have a deployment mode
where
its rate of communication to the gateway 150 would be faster for a period of
time, thereby
giving the installer more feedback as to the success and quality of the
installation. The
device could have a button that is used to activate the deployment mode for
this period of
time. The installer would then be able to move the device around until a
suitable position
is found, with the device and/or gateway determining and reporting the status
of the
communications link at a more frequent rate than might be had in the normal
operating
mode. The installer would be aware of a suitable position through data
reported by the
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device, such as via LED's or the display on device. Deployment mode may only
last for
a period of time that is sufficient to find acceptable location and
communicate with the
network. The deployment mode may automatically shut off to prevent installed
devices
being left in deployment mode.
[0045] In both of the cases above the network would have to be installed as
follows:
The gateway 150 is installed.
1. Devices can then be installed from the gateway 150 out so that as each
device is installed, they are able to communicate with the gateway 150; and
2. If it is not possible to install the devices, then temporary repeaters are
put in
place of where devices or repeaters will have to be installed to complete the
network.
[0046] Alternatively, the gateway 150 may have a deployment mode where
statistics
are gathered for each node in the network. The gateway may perform ping
statistics on
nodes, request diagnostic packets containing such things as signal strength, #
of hops etc.
After meters are installed, the gateway would then have to be taken out of
deployment
mode to gather energy information.
[0047] Locating installed devices may prove to be difficult especially if a
meter is
installed in a location different than the intended location. To assist in
locating devices
each meter could be outfitted with GPS chips. The location of the device could
then be
reported through the wireless link. A handheld GPS unit could then be used to
assist in
locating the device.
[0048) Figure 2 shows a block diagram of an energy monitoring device 120
according
to one embodiment. The energy monitoring device 120 includes electrical
current
interface circuitry 210 and electrical voltage interface circuitry 270. The
electrical
current interface circuitry 210 and electrical voltage interface circuitry 270
are operative
to interface with power conductors which supply electrical energy to a certain
load or area
of the building 100. This interface may be direct or through appropriate
current or
voltage transformers. In alternative embodiments, the energy monitoring device
may lack
either the electrical current or electrical voltage interfaces 210, 270
depending upon the
implementation and monitoring requirements of the device 120. The energy
monitoring
device 120 further includes an analog to digital converter 220, a micro-
controller 230
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coupled with the analog to digital converter 220, and RF communications
circuitry 240
coupled with the micro-controller 230. The electrical current interface
circuitry 210 and
electrical voltage interface circuitry 270 scale the signals from the power
conductors to
voltage levels compatible with the analog to digital converter 220. The analog
to digital
converter 220 provides digital representations of the voltage and current in
the power
conductors to microcontroller 230. Using these signals, the microcontroller
230
calculates at least one power parameter such as kWh, kVAh, kVARh, kW demand,
kVA
demand, kVAR demand, etc. The microcontroller 230 transmits this power
parameter
through RF communications circuitry 240 through the mesh network and gateway
150 to
computer 160. The computer 1 SO may send configuration and command data (such
as
demand reset) to the energy monitoring devices 120 through the mesh network.
The
microcontroller 230 also maintains time for the energy monitoring device 100
in a
memory register 280 which may be internal to and/or external to the
microcontroller 230.
The microcontroller 230 also maintains a private key 281 in internal and/or
external
memory. The energy monitoring device 100 also contains a power supply 260
which
may interface to the same voltage signals as the voltage interface circuitry
270 or to an
alternative power source. The power supply 260 may incorporate a battery or
capacitor to
facilitate operation when operating power is lost. The power supply 260 may
also
incorporate crystal radio type circuitry as an alternate source of operating
power such that
RF power present from local AM radio stations may be utilized to power the
energy
monitoring device 120. Additional circuitry 250, such as wireline
communications, I/O
circuitry, etc. may also be provided in the energy monitoring device 120. A
label 282 is
provided on the outside of the energy monitoring device 120. The label may
provide the
public key corresponding to the private key 281. Alternatively, the public key
may be
shown on a display coupled to the microcontroller 230 or periodically
broadcast over the
communications links 140 forming the mesh network, either automatically or in
response
to a request. In one embodiment, the public key and associated private key may
be
periodically changed by the microcontroller 230. The microcontroller 230, may
use A/D
220 readings, RF noise readings, etc. as random numbers to generate these
public/private
key pairs or, alternatively, the key pairs may be inserted during manufacture
or may be
input to the energy monitoring device 120 using other methods.
14
CA 02532984 2006-O1-18
[0049] In one embodiment, a voltage displacement device is utilized to allow
any
piece of monitoring equipment to be connected to a voltage conductor without
the need to
power down the line to be monitored. This piece of equipment could be an
integral part
of the monitoring devices voltage leads or a separate device that would allow
for a
galvanic connection between the voltage source and the monitoring device. An
exemplary voltage displacement device 1102 is shown in Figure 11 attached to a
power
line 1104. The voltage displacement device 1102 pierces the power conductor I
104, in a
safe and insulated manner, to provide a means of powering the monitoring
device as well
as providing a signal to monitor and/or measure. The device 1102 is clamped
and locked
to the power conductor 1104 utilizing a locking/clamping mechanism 1106 in a
manner
that would require a tool for removal, thereby preventing unauthorized persons
from
tampering or removing the connection. Even when local electrical codes,
procedures
and/or standards require powering down a conductor before adding a connection
to it, the
voltage displacement device may save installation time and cost since no
splicing,
terminal connections, etc. are necessary to make the connection.
[0050] In one embodiment, a power meter is provided which includes multiple
radios
for redundant operation in case of a failure or to facilitate communications
over multiple
RF channels simultaneously. Alternatively, a low power and a high power radio,
possibly
similar to the low/high power radio described above for device installation,
may be
provided, wherein the device determines the optimum radio to use based on
ambient
environmental conditions, time of day or other trigger.
(0051] If, for some reason, nodes in the main radio network stop communicating
energy/power data there may be an alternate method to extract data manually or
through
some other low cost method. Due to the nature of mesh networks if nodes in the
middle
of the network lose power, all nodes that communicate through those nodes may
also stop
communicating. Using a point to point radio technology would enable a person
to go
from floor to floor collecting energy/power data from the non-communicating
devices
until the mesh wireless network problem is resolved. In particular the second
radio
technology could be Bluetooth, 802.1 lx (a, b or g), infrared, or similar
networking
technology, so that the data collector could use a handheld device to
communicate with a
single device if the address is known (point-to-point).
CA 02532984 2006-O1-18
16
[0052] In one embodiment, the gateway device 150 may provide a firewall
capability,
or this capability may provided by a separate device logically located so as
to be able to
control and contain network traffic, which prevents unauthorized access to the
mesh
network from an external network, such as via the gateway device. The firewall
device
may further permit limited unauthenticated wireless access or limit access
based on the
level of security or level of trust in a given entity or method of access.
[0053] Often in establishments, the department responsible for internal
networks will
be wary of attaching devices to their internal network. However, this
department may be
receptive to providing a network connection to a demilitarized zone or
directly to the
Internet. In this case the firewall within or coupled to the gateway protects
the gateway
150 and mesh network devices from unauthorized access. The gateway may report
to the
computer (which may be within the corporate network) through protocols such as
SMTP,
HTTP, etc. which most corporate firewalls do not block.
[0054] Often there is no Ethernet connection where the gateway is to be
installed.
Instead of running a wired connection to the demilitarized zone, a secure
wireless
technology such as WI-FI may be used.
[0055] In yet another alternative embodiment, the capability for a monitoring
device
or other node to act as a gateway for legacy devices, which do not feature the
capability to
communicate via the mesh network, is provided. The gateway-enabled device may
act as
a simple conduit allowing bi-directional communications with the legacy device
as if the
legacy device were itself on the network. This may be accomplished via
protocol
encapsulation. Alternatively, the gateway-enabled device may act as a master
device,
server or other intermediary which mediates communications between the network
and
the legacy device(s). For example, the gateway-enabled device may aggregate
data
retrieved from multiple legacy devices and pass the aggregate onto the
network.
[0056] In RF challenged zones, I.e. where RF based communications are
difficult, or
for supporting legacy devices, it may be desirable to communicate to meters
via the RS-
485 serial bus. In one embodiment, a gateway device is provided that supports
both
wireless technology and multiple/single RS-485 connections for legacy devices
or in
areas were wireless does not work. The gateway device, as described, may act
as a single
data collector for multiple nodes communicating via RS-485 and wireless links.
The
16
CA 02532984 2006-O1-18
17
gateway device may be an application specific device for bridging other
devices onto the
mesh network or may be an additional function provided by a mesh network node,
such
as the monitoring device described above.
[0057] In yet another embodiment, a monitoring device or other node device is
provided with flexible power options allowing it to draw operating power from
various
sources, without interfering with those power sources. This adds to the
flexibility of the
device to be placed in locations which may not have convenient sources of
operating
power, the sources of operating power may not be reliable or stable, and/or
the sources of
operating power are the same as that being monitored and isolation of the
device is
desirable. Such sources of electrical power may include emergency power
sources such
as power for exit or emergency lighting systems, solar power (via a window or
ambient
lighting), telephone system power, battery power, RF power (similar to the
operation of
Radio Frequency Identification Devices ("RFID'~ or crystal radio sets) or
combinations
thereof. In this way, there is reasonable assurance that the device will
receive a constant
uninterrupted supply of operating power. Such devices may be further provided
with
flexible mounting options such as the ability to be mounted to a light bulb
socket or wall
socket/outlet. The ability to lock the device in place and draw operating
power therefrom
may also be provided. An example repeater 155 that may be plugged into a wall
506
outlet 502 having one or more power sockets 504 is shown in Figures 5 and 6.
The
repeater features an antenna 508 and power connectors 510. In this
configuration, the
repeater 155 draws power from at least one of the sockets 504 and is secured
in place
with a replacement screw 514 for the wall outlet 502. The repeater 155 can
thus not
easily be removed either accidentally or intentionally. The screw 514 may
incorporate a
one-directional drive engagement to further discourage removal. The repeater
155 may
also provide pass through outlets 512 such that the outlet 502 can still be
used. In an
embodiment which fits into a light socket, a pass through socket may be
provided to
allow the socket to be used for illumination purposes.
[0058] In one embodiment, mesh network enabled current transducers or
transformers
("CT's") include a physical security mechanism to prevent or indicate
tampering and/or
removal of the CT from the power line being monitored. Figures 9A-9C depicts
an
exemplary CT 900 having a revenue lock mechanism 955. Effectively, the CT
includes
17
CA 02532984 2006-O1-18
18
two interlocking portions 925 930, each of which come together to encircle the
power line
903 to measure the current passing there-through. The interlocking portions
925 930 each
feature a locking hole 955. The locking holes 955 of each portion come into
alignment
when the portions 925 930 are assembled around the power line 903 thereby
allowing a
sealing device 950, such as a lock or locking wire, to be fed through both
holes 955
preventing removal of the CT without breaking the locking mechanism 950 and/or
causing indication of tampering.
[0059) In yet another alternative embodiment, the capability to update and/or
modify
the firmware of a monitoring device or other mesh network node via a mesh
network is
provided. In operation, the particular monitoring devices) or other mesh
network nodes)
to be upgrade/modified may be instructed to enter an upgrade/modify mode.
Upgraded or
modified software/firmware may then be transmitted via the network to the
device as one
or more packets. The devices) receives and assembles these packets into a
memory, re-
requesting packets that are received with errors and determining and re-
requesting
missing packets. Once the new code has been fully transferred, the device is
instructed to
begin executing the new code. Prior to executing the new code, the device may
validate
or otherwise authenticate the code and may further perform functions to ensure
that the
device can recover should an error occur, such as by performing a data backup
operation.
In an alternate embodiment, the special upgrade mode is unnecessary. In this
case, the
packets of new code contain an indicator to the device as such. When the
device sees
such packets, it writes them to its memory store and assembles the complete
code, re-
requesting errant packets and tracking and re-requesting missing packets. Once
all of the
packets have been received, as determined by an indicator which tells the
device how
many were to be received or by an packet denoted as the last packet sent, the
device
automatically switches over to the new code. Prior to switching over to the
new code, the
device may validate the new code, or otherwise perform an authentication.
Further, the
device may perform a backup operation of any stored data to ensure that
recovery is
possible if an error occurs.
[0060) In one embodiment, a monitoring device is provided which is capable of
utilizing assumed voltage readings in situations where it is not possible to
determine
actual voltage readings from the circuit being monitored. This capability
allows the
18
CA 02532984 2006-O1-18
19
monitoring device to operate until it becomes possible to connect it to the
voltage
terminals of the circuit to be monitored, or operate indefinitely without
connection to the
voltage terminals, depending upon the application. When installing the energy
monitoring device 120, it is often necessary to power down the circuit to be
monitored so
that voltage connections can be made to the energy monitoring device.
Otherwise, the
installer may be exposed to hazardous voltages and/or the device 120 may
experience an
unexpected power surge on its inputs upon connection, thereby damaging the
device.
However, installation of the current connections can often be accomplished
with the
circuit energized when using non-contact sensors, such as "clamp-on" CTs which
rely on
induced current flow, as the risk of injury or damage is lessened.
[0061] Therefore, the energy monitoring device 120 according to the present
embodiment provides the ability to estimate power and/or energy readings when
only the
current inputs are connected. As described, this estimated-operation may be
used on a
temporary or permanent basis. If used on a permanent basis, the energy
monitoring
device 120 may be provided without voltage inputs so as to lower manufacturing
costs.
This may occur, for example, where the application demands may be met using
assumed
voltage values and, accordingly, the user does not wish to pay for or install
fully
functional devices 120.
[0062) In order to estimate power and/or energy readings, several techniques
may be
used. In one embodiment shown in Figure 13, the energy monitoring device 120
may be
programmed with an assumed voltage and/or power factor based on the particular
load it
is monitoring (1302). The device 120 may be programmed prior to, or after,
connecting
the current inputs to the circuit to be monitored (1304). The assumed values)
is/are
stored in a memory within the device and used by the processor as the basis
for
computing other data regarding the monitored circuit, as will be described.
Programming
assumed values into the device 120 may be accomplished directly using direct
communications inputs provided by the device 120 or through the mesh network
or other
network communications input. Once programmed, the device switches into an
assumed-
value mode of operation, either manually or automatically, as described above
(1306).
The assumed voltage and/or power factor values may then be utilized by the
device 120
to perform the requisite power and/or energy calculations (1308). The computed
results
19
CA 02532984 2006-O1-18
may then be reported as per the normal operation of the device 120 (1310). As
noted
above, the reported results may include an indicator which indicates that the
calculations
were based on assumed values and may further indicate a margin of error as
such. In an
alternate embodiment, multiple power factors, for different load currents, are
provided
and the energy monitoring device 120 interpolates between these power factors
based on
the current present in the circuit being monitored. For example, the energy
monitoring
device 120 may be provided with an assumed voltage of 480VAC, and an assumed
power
factor of 0.84 at full load current (e.g. 40Amps), an assumed power factor of
0.8 at 3/4 load
current and an assumed power factor of 0.72 at %z load current. The energy
monitoring
device 120 may then interpolate the power factor to provide interpolated
values for use in
power and/or energy calculations based on actual current values which may
range
between the programmed assumed values or outside of them.
(0063] Alternatively, the energy monitoring device 120 may be programmed with
an
assumed voltage waveform and time relationship to the actual waveform
representative of
the actual current present in the circuit being monitored. Figure 10 shows
several
example voltage waveforms and time relationships 890 for several possible
current
waveforms 895. The energy monitoring device may use techniques such as fuzzy
logic,
artificial intelligence, point by point comparison, etc. to determine the
closest match
current waveform in a stored suite of waveforms and then use the corresponding
voltage
waveform including the assumed phase or time relationship to the current
waveform in
power and/or energy calculations. In yet another alternative embodiment, an
assumed
voltage magnitude may be programmed into the energy monitoring device 120 over
the
mesh network or the energy monitoring device 120 may be manufactured for a
given
voltage. This voltage magnitude may then be applied to the assumed voltage
waveform
during the calculation of power and/or energy (ie., each point in the assumed
voltage
waveform may be multiplied by a constant such that the rms value of the
voltage
waveform used in the power/energy calculations is the same as the voltage
magnitude
provided).
[0064] Further, when the monitoring device 120 is operating using assumed
voltage
data, an indicator may be appended to all calculation results to indicate to a
user or a data
aggregation system that the data that the monitoring device 120 is producing
is based on
CA 02532984 2006-O1-18
21
assumed values. Further, a visual indicator on the monitoring device 120
itself may
indicate such operation as well.
[0065) In one embodiment, the assumed values are stored in a memory within the
device 120 and referenced by the device 120 for performing calculations as
described
when the device 120 is placed in a "assumed voltage" mode of operation, either
automatically or manually by a user via the device's 120 user interface or
remotely over a
network. This mode of operation may automatically be activated when the device
120 is
suitably programmed with assumed data values and the device receives inputs on
its
current inputs but not on its voltage inputs, such as when the voltage inputs
are not
connected or the inputs or connections to the circuit fail or otherwise become
disconnected. Further, the assumed values may be stored as digital values
which bypass
the device's 120 analog to digital converter to be directly input into the
processor of the
device 120 or the assumed values may be stored in an analog form and act as
pseudo
inputs to the analog to digital converter when actual voltage measurements are
not
present. In one alternative embodiment, assumed voltage values are input into
the
monitoring device 120 by attaching a dummy voltage generator to the voltage
inputs of
the device 120 to feed an assumed voltage value to the device 120. This has
the
advantage of allowing the use of assumed voltage values on older devices 120
which lack
the capability to be programmed to do so.
(0066] In addition to using the steady state current waveform to determine an
appropriate voltage waveform and/or phase relationship to assume, the energy
monitoring
device 120 may analyze current waveforms during startup conditions,
transients, surges
or sags in current level to determine the types) of loads that are being
powered.
Assumed steady state voltage waveforms/phase relationships may be selected
based on
these conditions only or in combination with steady state current readings.
[0067] Several procedures for retrieving energy related data from energy
monitoring
devices 120 in the building 100 will now be discussed. It will be appreciated
that the
described procedures may be used alone or in combination without departing
from the
spirit and scope of the invention.
[0068] Figure 3 shows a first procedure for retrieving energy related data
from an
energy monitoring device 120. The energy monitoring device 120 may be
installed and
21
CA 02532984 2006-O1-18
22
interfaced to voltage and current signals (block 300) in order to monitor or
measure at
least one power parameter (block 310). The power parameter may be kWh, kVAh,
kVAIZh, kW demand, kVAR demand, kVA demand, voltage, current, etc. The energy
monitoring device contains a number of registers which store various measured
and
computed data values. This installation may be in electrical room 130 or any
other
appropriate installation location. The energy monitoring device creates a
security register
data (block 320) and stores this data in a security register in the device
120. This security
register data is created by the operation of the private key 281 on the
measured power
parameter(s), for example, the private key 281 may be hashed together with the
measured
power parameter(s). The private key 281 may be any of the pieces of
information
described above. The register (including the security register) contents are
then retrieved
from the energy monitoring device 120 (block 325). The registers may be
retrieved using
any appropriate method. Some example methods include reading with a portable
computing device 180 over a wireless link, manual recording on paper or into a
handheld
device or direct communication over a communication link to a central
computer. The
retrieved register contents are then returned to the utility or other entity
that bills for
energy usage (block 330). This may be accomplished by returning the paper or
portable
computing device 180, or storage media therefrom, to the utility or receiving
the register
contents over a communications link at the utility. The register contents,
including the
security register data from the security register, are then downloaded into a
computer
(block 340) where the register contents are authenticated using an appropriate
public key
(block 350) or using a shared private key. The public key may be any of the
pieces of
information described above.
[0069] Using this procedure, the possibility of an individual (such as a meter
reader)
tampering with energy readings is reduced due to the fact that the individual
would either
have to know the private key of the device, or be able to compromise the
particular
public/private key algorithm used in order to change the energy readings
without
detection.
[0070] Figure 4 shows a second procedure for retrieving power parameters from
an
energy monitoring device 120. This procedure may be appropriate for use when a
consumer of energy wishes to verify that they are being billed correctly for
energy usage.
22
CA 02532984 2006-O1-18
23
The energy monitoring device is installed and monitors at least one power
parameter
(blocks 300, 310) in a similar fashion as described in the previous procedure.
The energy
monitoring device 120 signs the power parameters) (block 400) utilizing a
digital
signature and transmits the power parameters) and signature over the network
(block
410). As used herein, to "sign", or alternatively, "digitally sign", a
message/document
means to generate or otherwise append a "digital signature" to the
message/document. A
digital signature is an electronic signature appended to a message/document
that can be
used to authenticate the identity of the sender of a message/document, the
signer of a
document/message, ensure that the original content of the message/document
that has
been sent is unchanged and/or prevent repudiation of the document's/message's
contents
by the sender. The signed document/message, with or without the digital
signature may,
but need not, be encrypted, either before or after signing. A digital
signature is typically
generated based on the contents of the document/message and the sender's
private key of
the public/private key pair. Upon receipt, the receiver of the message
"authenticates" the
message contents using the sender's public key. The network may be the mesh
network
previously described wherein the packets are transmitted via other energy
monitoring
devices or any other appropriate communications means. This information is
received by
a computer which makes the information available to a consumer of energy (or
other
entity that wishes to verify energy readings). For example, the information
may be made
available by way of a website hosted on an appropriate server. The consumer of
energy
(or other entity that wishes to verify energy readings) retrieves a public key
from the
device (block 420). This public key may be on a label 282 or may be provided
by any
other appropriate mechanism as described above. The user may then use the
public key
to authenticate the information on the website (block 430) and retrieve the
authenticated
energy readings (block 440).
[0071] In order to secure packets transmitted between them, the energy
monitoring
devices 120 may use a shared key. In this example, before sending a packet to
the next
energy monitoring device 120, the originating energy monitoring device 120
encrypts the
packet (or portion thereof] with the shared key. The receiving energy
monitoring device
120 then decrypts the packet (or portion thereof) and only forwards the packet
on to the
next energy monitoring device 120 if the decryption process results in valid
information.
23
CA 02532984 2006-O1-18
24
In this way, energy monitoring devices 120 or rogue devices rnay not insert
themselves
into the mesh network unless they know the shared key (or defeat the
encryption/decryption algorithm).
[0072] The energy monitoring devices 120 may incorporate a GPS receiver or
other
mechanism for determining position (such as RF triangulation techniques). The
position
of each energy monitoring device 120 may be incorporated and secured in
packets
transmitted from the energy monitoring device using techniques such as those
previously
described. Any receiving device may then ignore data from a device that is not
in an
expected geographical location. This information may also be used to detect
tampering
such as for instance an energy monitoring device 120 being moved from its
expected
location. In addition, the portable communication device 180 may also
incorporate a GPS
receiver. The portable communication device may then compare its position to
that of the
energy monitoring device it is querying in order to verify it is querying the
correct meter.
This comparison may also be performed later after the data from the portable
communication device 180 has been transferred to a computer.
[0073] At least one of the energy monitoring devices 120 may use pattern
recognition
or other techniques to scan packets they are forwarding to additional energy
monitoring
devices 120. These techniques may be used to detect rogue packets or packets
containing
malicious code. This may help prevent tampering with the system and may help
prevent
viruses from propagating through the system.
[0074] A mesh network provides redundancy in communications between devices.
For enhanced reliability of the network it is desirable to have more than once
communications path from each device. The computer 160 of the present
invention may
receive diagnostic information from the devices in the mesh network such that
identification of devices with only one communications path leading from them
may be
identified to the user. Additional repeaters 155, gateways 150 or energy
monitoring
devices 120 may then be added to the system to improve reliability.
[0075] Figure 12 shows an alternative exemplary commercial office building
100a for
use with the disclosed embodiments. The office building 100a receives main
power from
a grid intertie 1200 which interconnects the building's 100a internal power
distribution
network with the utility's power distribution grid. A service entrance
infrastructure 1210
24
CA 02532984 2006-O1-18
couples to the grid intertie and provides multiple 3 phase buses 1220 for
powering various
loads in the office building 100a. In typical installation, only one energy
meter is
provided in the building to measure power parameters of power flow from the
grid
intertie 1200 to the service entrance infrastructure 1210.
[0076] Subsequent to the service entrance metering, power is. distributed
inside the
building through various vertical shafts either with traditional conductors
(older
buildings) or via bus ducts (newer installations). The shafts are much like
elevator shafts,
vertically on top of each other spanning multiple floors, except that the
shaft is only
physically big enough to allow the conductors to pass through the floors
{whereas an
elevator shaft is completely open).
[0077] On each floor the power is distributed further to provide energy for
lighting,
plugs and other tenant loads.
[0078] Most of the shared building loads 1230 of the commercial office
building 100a
are located on the roof. These loads include air conditioners, elevator
motors, etc. The
lease management office 1250 and engineering office floor 1240 are typically
the only
areas where the building owner or operator has office space. Therefore,
gateways 150,
computers 160, LAN 170 and WAN 171 connections for energy monitoring use are
typically also located on these floors.
[0079] Energy consumption information may flow from the mesh networked devices
(energy monitoring devices 120, repeaters 155 and gateways 150) through the
computers
160, LAN 170, WAN 171 to a remote data processing center 1260 where usage
information such as bills may be generated. This usage information 1270 is
then returned
to the building users 1280 through appropriate communication means. This
information
may also be delivered to corporate users 1290 such as the building
owners/operators. A
mesh network or other communications connection may be made to the service
entrance
meter 1215 in order that the computer 160 and/or remote data processing center
1260 may
correlate the readings therefrom with those from the various energy monitoring
devices
120. For instance if all loads within the office building 100a are monitored
with energy
monitoring devices 120, the combination of the energy monitoring devices
readings
should correlate with those of the service entrance meter 1215.
CA 02532984 2006-O1-18
26
[0080] The building users may be presented with billing information that
categorizes
their actual energy usage and share of common loads by the remote data
processing center
1260 by using the information from the energy monitoring devices 120.
[0081] Three phase transformers 1205 may be provided at various points in the
office
building IOOa. In these cases it may be desirable to have energy monitoring
devices 120
on both the inputs and outputs of the transformers to account for loses
therein.
[0082] In one embodiment, the office building I OOa, may contain one or more
than
one electrical closet shafts 1225. These shafts may split or be widely
separated from one
another. It may therefore be necessary to have multiple mesh networks within
the
building that comprises separate sets of energy monitoring devices 120,
repeaters 155,
gateways I50 and computers 160. Wireline segments or other means of bridging
gaps in
the mesh network may alternatively or in addition be used as described above.
[0083] When commissioning the system, battery powered mesh networking devices
such as battery powered repeaters I55 may be temporarily installed in the
building in
order to "prove" out the network and identify areas where particular attention
will have to
be paid to establishing network links.
[0084] In addition, in some implementations, the low power RF' signals of the
mesh
network may have difficulty traveling in a horizontal direction from the
associated
antennas of the devices 120 due to inherent limitations in the transmissive
properties of
such signals. Such limitations may result in a restricted transmission range.
However,
typically the vertical transmissive properties of the RF signals are
acceptable. In one
embodiment, the mesh network is formed via the vertical electrical shafts
which allow for
the vertically radiated RF signals to travel relatively unimpeded. The mesh
network is
carried to the roof of the facility or to another area having no substantial
RF impediments,
where the mesh network is bridged, either via a wired or wireless connection
to other
electrical shafts which have similarly formed mesh networks. In this way, the
vertical
transmissive properties of the 1RF signals are advantageously utilized and
reliance on the
horizontal transmissive properties are minimized. Alternatively, for buildings
such as
malls with a small number of floors, but a wide horizontal expanse, mounting
devices 120
and/or repeaters 155 to form the mesh network along the roof also provides for
an
efficient network structure. Devices I20 monitoring rooftop loads such as air
26
CA 02532984 2006-O1-18
27
conditioners may perform "double duty" by extending the mesh network as well
as
monitoring a load. Repeaters 155 may be solar powered when mounted in rooftop
locations or otherwise as described herein.
[0085] The following describes one exemplary implementation of a system
incorporating aspects of the present invention. One exemplary implementation,
which
employs one or more of the disclosed embodiments, utilizes the ION 6100
Wireless
Metering System, manufactured by Power Measurement, Ltd., located in
Saanichton,
British Columbia, Canada, which offers outstanding quality, versatility, and
functionality
in a low-cost wireless power and energy metering system ideal for sub-billing
applications. This system is based on the PML ION 6100 Wireless Power
Meter/monitoring device 120 and meets ANSI C 12.16 Class 1 energy accuracy.
This
system may be utilized by Commercial (Office & Retail) Properties market in
North
America, and is ideal for customers who need revenue-accurate measurements for
tenant
sub-billing.
[0086] The system includes wireless metering devices, non-intrusive current
transformers (CTs), and a central gateway that gathers, aggregates and logs
meter data
and exports it in an industry-standard XML format for integration into any
software or
billing system (including Power Measurement's ION EEM software).
[0087] The meters collect time-stamped, interval-based consumption data (kWh)
from
key sub-metering or sub-billing points throughout a building, then communicate
the
information to the central gateway (PC) via a proprietary wireless 900MHz
radio
network. All meters are time-aligned with the gateway clock, so the system can
also
provide coincident demand readings.
[0088] The system offers customers a lower total cost of ownership (TCO)
because:
wireless communications eliminate the need to run costly communication wire
and
conduit throughout a facility; easy-to-use, split-core; current transformers
(CTs) simply
clamp onto existing wires for non-intrusive current measurements, simplifying
installation; the ultra-compact meter design can attach to virtually any
enclosure more
than four inches deep with a single bolt; and automated gathering of meter
data removes
the need for manual meter reading.
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[0089] The exemplary ION 6100 Wireless Metering System offers: high quality
and
accuracy, low installation costs (contributing to a lower Total Cost of
Ownership); a
complete system (meters, communications, gateway) (contributing to a lower
Total Cost
of Ownership); industry-standard XML data export for easy integration into any
software
system (such as the ION enterprise energy management system ("EEM"),
manufactured
by Power Measurement Ltd, located in Saanichton, British Columbia, Canada);
and time
synchronized for coincident demand calculations.
[0090] Unlike other power meters, which are sold separately and to a wide
range of
markets, this device is made available as part of a larger sub-billing
solution for the
commercial property market in North America.
[0091] The exemplary ION 6100 power meter offers:
Sub-Billing and Cost Allocation
Costs (including usage and demand charges) can be fairly accounted
for and apportioned among tenants appropriately, increasing tenant
satisfaction and lowering operating costs.
Low Total Cost of Ownership (TCO)
The system offers customers a lower total cost of ownership (TCO)
because:
All necessary components can be purchased at once, on a
single P.O.;
Wireless communications eliminate the need to run costly
communication wire and conduit throughout a facility;
Easy-to-use, split-core, current transformers (CTs) simply
clamp onto existing wires for non-intrusive current
measurements,
simplifying installation;
Simple installation ensures no disruptions to regular business
processes;
Ultra-compact meter design can attach to virtually any
enclosure
more than two inches deep through a standard knockout with
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a '/2"
threaded conduit lock ring;
Automated gathering of meter data removes the need for
manual
meter reading.
Reliability
The ION 6100 offers a reliable "self healing" approximately 900 MHz
wireless radio network.
Each meter can relay a signal to the next closest meter, allowing signals to
be easily
transmitted from one end of a building to another. If a meter becomes
unavailable,
the other meters can communicate "around" it, so that there is no
significant
disruption in data transmission.
Useful Data
Besides sub-billing and cost allocation, data can be also used as an input to
building
automation and control systems, leveraging and maximizing the value of
existing
systems. The gateway can be used to capture a quick snapshot of overall
operating
performance and / or identify power problems at a particular load.
The ION 6100 Wireless Metering System is currently aimed at the North
American
commercial office and retail properties market, for buildings with greater
than
500,000 square feet of leasable space and at least 20 tenants.
The key application for this system is sub-billing, but many commercial
enterprises
are also beginning to leverage these systems as core elements of a more
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CA 02532984 2006-O1-18
comprehensive EEM solution focused on reducing energy costs and
improving their
net operating income (NOI) and overall asset value.
Value Proposition
For commercial building managers and owners in North America who need
an
accurate and automated system for fairly recovering energy costs from
tenants. This
system combines an accurate and reliable meter with a robust wireless
communication network to create an automated sub-billing system with a
low
installation cost and a low total cost of ownership (TCO). Unlike
traditional sub-
metering devices, which must be manually read or that may lack the
software
required for efficient sub-billing or more powerful enterprise energy
management.
The ION 6100 Wireless Metering System is an integrated end-to-end
solution for
tenant sub-metering and a key piece of a comprehensive Enterprise Energy
Management (EEM) system
[0092] Exemplary relevant applications of the exemplary system include Primary
Application: Sub-Billing
(0093] Typical scenario before installing ION 6100 Wireless Metering System
solution:
Existing No Metering Existing Metering - No
System
Situafion
Desired The property owner needsThe property owner needs
to recover the to recover the
Outcome costs of supplying electricitycosts of supplying electricity
to the to the
individual tenants for individual tenants for
the lowest cost the lowest cost
possible. possible.
CA 02532984 2006-O1-18
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AttemptedEnergy and demand costs Meters are manually read
are either not either by a sub-
Approach passed through to the billing service provider
tenants, or costs or by a
are allocated to the designated individual
tenants based on a or individuals
common formula - normallyemployed by the property
based on the management
square footage of the company.
tenant relative to
the total leasable space
of the building.
InterferingSome States prohibit Even with existing metering
allocation methods that has
Factors of cost recovery (Note: communications ability
some prohibit the cost of
sub-billing as well). implementing communications
Traditionally, the can be
costs to implement a high.
sub-metering
system are high.
Economic Tenants are getting smarterThe labor and data integrity
and asking to costs of
Consequencesbe billed only for theirmanaging these manual
own usage. systems are high.
Allocation methods are The lack of resolution
inaccurate and in the data (i.e. one
generally considered monthly kWh reading) provides
unfair. Accurate no
and reliable sub-billinginsight into the opportunities
is somewhere that may be
between being a competitiveavailable to better manage
and a de- costs.
facto standard. Allocation of coincident
demand costs is
not possible.
[0094] Typical scenario after installing the exemplary ION 6100 Wireless
Metering
System solution:
New A low TCO, highly accurateA low TCO, highly accurate
and reliably and reliably
Approachautomated sub-billing automated sub-billing system
system
EnablingLow cost metering devicesLow cost metering devices
that are that are
Factorsinexpensive to install inexpensive to install
(non-intrusive CTs, (non-intrusive CTs,
wireless communications) wireless communications)
and maintain. and maintain.
Powerful and user-friendlyPowerful and user-friendly
data collection data collection
and billing software for and billing software for
providing detailed providing detailed
cost data. cost data.
EconomicEnables energy cost recoveryCompetitive or sustained
in States that advantage
Rewardsdo not allow allocation relative to tenant satisfaction.
methods. Reduces
Competitive or sustained costs due to manual reading
advantage and potential
relative to tenant satisfaction.data entry errors. Detailed
Detailed interval data
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interval data enables accurate coincident enables accurate coincident demand
cost
demand cost recovery. Detailed interval recovery. Detailed interval data
enables
data enables insight to identify energy insight to identify energy savings
savings opportunities. opportunities.
[0095] Secondary Applications include: Contract and Bill Validation, which can
help
customers verify that energy management improvements are generating the
projected
payback., high-accuracy measurements can also be used for utility bill
verification; and
Cost Allocation which can help monitor cost centers right down to the tool
level, identify
opportunities for demand control, and check energy consumption patterns.
[0096] The following tables describe features and benefits of the exemplary
ION 6100
monitoring device as both a metering device and as a gateway device.
[0097] ION 6100 Metering Device
Feature Advantage Benefit
ION 6100 All the metering piecesSimple to purchase, inexpensive
meter, in one neat to
NICTs, wirelesslittle package install and operate -
Installed costs of
communications $300 to $500 per metering
point as
gateway compared with traditional
sub-metering
solutions
Non-intrusiveThe ION 6100 meters Low installation cost,
can be installed no installation
current without requiring an disruption
& voltage outage in power to
transformersthe load
(NIC VTs/NICTs)
and/or voltage
displacement
connections
Wireless No holes to drill, no Low installation costs,
radio conduit or wires to no
network run, instant and automaticcommunication configuration
network on the
communicationsconfiguration device - Reliable "self
healing"
network communications
Exceeds Accuracy is verified Costs can be fairly accounted
ANSI to national sub- for and
C 12.16 metering standards apportioned appropriately
( 1 %)
accuracy
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standards
or
appropriate
local
standard.
24 hour Data is stored on the Low risk of data loss
internal device as a
data storagebackup in case of a
temporary
communication interruption
Devices Independent device clocksBuilding demand charges
are time are can be
synchronizedcoordinated to enable accurately apportioned
to accurate among tenants
the ION coincident demand calculations
6100
Gateway
for
coincident
demand
calculation
[0098] ION 6100 Gateway
FeatureAdvantage Benefit
All Gateway software can be Data can be used for sub-billing,
data configured to as an
is
collectedexport data to multiple input to building automation
systems and control
in a systems, etc.
central
data
file
and
exported
as
required
DiagnosticOther power, energy, communicationT'he gateway can be used
and to capture a
data other diagnostic data quick snapshot of overall
can can be viewed on the operating
be gateway from any device performance and / or identify
in the network power
requested problems at a particular
load.
from
devices
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[0099] It is therefore intended that the foregoing detailed description be
regarded as
illustrative rather than limiting, and that it be understood that it is the
following claims,
including all equivalents, that are intended to define the spirit and scope of
this invention.
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